Health Monitor

ABSTRACT

Methods and devices to detect analyte in body fluid are provided. Embodiments include enhanced analyte monitoring devices and systems.

RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 12/143,734 filed Jun. 20, 2008, entitled “Health Monitor”,which claims priority to U.S. provisional application No. 60/945,581filed Jun. 21, 2007, entitled “Health Monitor” and assigned to theassignee of the present application, Abbott Diabetes Care Inc., thedisclosure of which is incorporated herein by reference for allpurposes.

BACKGROUND

The detection of the level of analytes, such as glucose, lactate,oxygen, and the like, in certain individuals is vitally important totheir health. For example, the monitoring of glucose is particularlyimportant to individuals with diabetes. Diabetics may need to monitorglucose levels to determine when insulin is needed to reduce glucoselevels in their bodies or when additional glucose is needed to raise thelevel of glucose in their bodies.

Accordingly, of interest are devices, system and methods that allow auser to test for one or more analytes.

SUMMARY

Embodiments include enhanced in vitro analyte meters and systems whichare enhanced with in vivo continuous analyte monitoring functionality.The descriptions herein describe in vitro analyte glucose metersprimarily as in vitro blood glucose (“BG”) meters and in vivo continuousanalyte system primarily as in vivo continuous glucose (“CG”) monitoringdevices and systems, for convenience only. Such descriptions are in noway intended to limit the scope of the disclosure in any way.

Accordingly, BG meters and systems having high levels of functionalityare provided. Each BG or CG system may accept and process data from itsown respective system and/or from another system, e.g., a BG system mayaccept and process CG system data, or vice versa. Embodiments enable CGdata to be provided to a user by way of a BG meter.

Embodiments may be useful to users who may require conventional bloodglucose BG data most of the time, but who may have a periodic need forCG data. One way this problem has been addressed in the past is toprovide the user with both a BG meter and a CG system. However, this hasthe disadvantage of cost because a CG system may be more expensive thana BG meter, and increased training as the user must learn how to use twometers—a BG meter for normal use and a CG meter for those times when CGdata is required.

Embodiments herein may be appropriate for Type I and Type II diabetics,other patients experiencing diabetic conditions, or patients in postsurgery recovery period.

Also provided are devices, methods and kits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an embodiment of a data monitoring andmanagement system according to the present disclosure;

FIG. 2 shows a block diagram of an embodiment of the transmitter unit ofthe data monitoring and management system of FIG. 1;

FIG. 3 shows a block diagram of an embodiment of the receiver/monitorunit of the data monitoring and management system of FIG. 1;

FIG. 4 shows a schematic diagram of an embodiment of an analyte sensoraccording to the present disclosure;

FIGS. 5A-5B show a perspective view and a cross sectional view,respectively of another embodiment an analyte sensor;

FIG. 6 shows an exemplary embodiment of a system that includes a CG DataLogger (for example, including a data storage device or memory) and anenhanced BG meter, in which the CG Data Logger is capable oftransferring CG data obtained by a CG analyte sensor positioned at leastpartially beneath a skin surface of a user to the enhanced BG meter;

FIG. 7 shows an exemplary embodiment of a Modular System that includes aCG unit having a transmitter, data transfer module and enhanced BGmeter, in which the CG unit is capable of wirelessly transferring dataobtained by a CG analyte sensor positioned at least partially beneath askin surface of a user to the enhanced BG meter by way of the datatransfer module;

FIG. 8 shows an exemplary embodiment of an integrated system thatincludes an enhanced BG meter and a CG unit having a transmitter, inwhich the CG unit is capable of transferring CG data obtained by a CGanalyte sensor positioned at least partially beneath a skin surface of auser to the enhanced BG meter in real time;

FIG. 9 shows an exemplary embodiment of a system which includes a BGmeter and a docking unit, herein shown configured as a belt holster;

FIGS. 10A-10C show exemplary embodiments of glucose test strips that maybe used with the enhanced systems described herein; and

FIGS. 11A-11C show exemplary BG meters.

DETAILED DESCRIPTION

Before the present disclosure is described, it is to be understood thatthis disclosure is not limited to particular embodiments described, assuch may, of course, vary. It is also to be understood that theterminology used herein is for the purpose of describing particularembodiments only, and is not intended to be limiting, since the scope ofthe present disclosure will be limited only by the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the disclosure. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges is also encompassed within the disclosure, subject to anyspecifically excluded limit in the stated range. Where the stated rangeincludes one or both of the limits, ranges excluding either or both ofthose included limits are also included in the disclosure.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentdisclosure.

The figures shown herein are not necessarily drawn to scale, with somecomponents and features being exaggerated for clarity.

Embodiments include devices which allow diabetic patients to measure theblood (or other bodily fluid) glucose levels, e.g., hand-held electronicmeters (blood glucose meters), e.g., such as Freestyle® or Precision®blood glucose monitoring systems available from Abbott Diabetes Care,Inc., of Alameda, Calif. (and the like) which receives blood samples viaenzyme-based test strips. Typically, a user inserts a test strip into ameter and lances a finger or alternate body site to obtain a bloodsample. The drawn sample is applied to the test strip and the meterreads the strip and determines analyte concentration, which is thenconveyed to the user. For example, the blood glucose meter converts acurrent generated by the enzymatic reaction in the test strip to acorresponding blood glucose value which is displayed or otherwiseprovided to the patient to show the level of glucose at the time oftesting.

Such periodic discrete glucose testing helps diabetic patients to takeany necessary corrective actions to better manage diabetic conditions.

Test strips may be adapted to measure the concentration of an analyte inany volume of sample, including but not limited to small volumes ofsample, e.g., about 1 microliter or less sample, for example about 0.5microliters or less, for example about 0.3 microliters or less, forexample about 0.1 microliters or less. In some embodiments, the volumeof sample may be as low as about 0.05 microliters or as low as about0.03 microliters. Strips may be configures so that an accurate analytemeasurement may be obtained using a volume of sample that wholly orpartially fills a sample chamber of a strip. In certain embodiments, atest may only start when sufficient sample has been applied to a strip,e.g., as detected by a detector such as an electrode. A system may beprogrammed to allow re-application of additional sample if insufficientsample is firstly applied, e.g., the time to reapply sample may rangefrom about 10 seconds to about 2 minutes, e.g., from about 30 seconds toabout 60 seconds.

Strips may be side fill, front fill, top fill or corner fill, or anycombination thereof. Test strips may be calibration-free, e.g., minimalinput (if any) is required of a user to calibrate. In certainembodiments, no calibration test strips may be employed. In suchembodiments, the user need not take any action for calibration, i.e.,calibration is invisible to a user.

As noted above, strips are used with meters. In certain embodiments,meters may be integrated meters, i.e., a device which has at least onestrip and at least a second element, such as a meter and/or a skinpiercing element such as a lancet or the like, in the device. In someembodiments, a strip may be integrated with both a meter and a lancet,e.g., in a single housing. Having multiple elements together in onedevice reduces the number of devices needed to obtain an analyte leveland facilitates the sampling process. For example, embodiments mayinclude a housing that includes one or more analyte test strips, a skinpiercing element and a processor for determining the concentration of ananalyte in a sample applied to the strip. A plurality of strips may beretained in a magazine in the housing interior and, upon actuation by auser, a single strip may be dispensed from the magazine so that at leasta portion extends out of the housing for use.

Test strips may be short test time test strips. For example, test timesmay range from about 1 second to about 20 seconds, e.g., from about 3seconds to about 10 seconds, e.g., from about 3 seconds to about 7seconds, e.g., about 5 seconds or about 3 seconds.

Exemplary meters and test strips and using the same are shown in FIGS.10A-10C and 11A-11C.

Embodiments include analyte monitoring devices and systems that includean analyte sensor—at least a portion of which is positionable beneaththe skin of the user—for the in vivo detection, of at least one analyte,such as glucose, lactate, and the like, in a body fluid. Such in vivosensors are generally referred to herein as in vivo sensors/systemsand/or continuous sensors/systems, where such are used interchangeablyunless indicated otherwise. Embodiments include wholly implantableanalyte sensors and analyte sensors in which only a portion of thesensor is positioned under the skin and a portion of the sensor residesabove the skin, e.g., for contact to a transmitter, receiver,transceiver, processor, etc. The sensor may be, for example,subcutaneously positionable in a patient for the continuous or periodicmonitoring of a level of an analyte in a patient's interstitial fluid.For the purposes of this description, continuous monitoring and periodicmonitoring will be used interchangeably, unless noted otherwise. Thesensor response may be correlated and/or converted to analyte levels inblood or other fluids. In certain embodiments, an analyte sensor may bepositioned in contact with interstitial fluid to detect the level ofglucose, which detected glucose may be used to infer the glucose levelin the patient's bloodstream. Analyte sensors may be insertable into avein, artery, or other portion of the body containing fluid. Embodimentsof the analyte sensors of the subject disclosure may be configured formonitoring the level of the analyte over a time period which may rangefrom minutes, hours, days, weeks, or longer. Analyte sensors that do notrequire contact with bodily fluid are also contemplated.

Of interest are analyte sensors, such as glucose sensors, that arecapable of in vivo detection of an analyte for about one hour or more,e.g., about a few hours or more, e.g., about a few days of more, e.g.,about three or more days, e.g., about five days or more, e.g., aboutseven days or more, e.g., about several weeks or at least one month.Future analyte levels may be predicted based on information obtained,e.g., the current analyte level at time t₀, the rate of change of theanalyte, etc. Predictive alarms may notify the user of a predictedanalyte levels that may be of concern in advance of the user's analytelevel reaching the future level. This provides the user an opportunityto take corrective action.

FIG. 1 shows a data monitoring and management system such as, forexample, an analyte (e.g., glucose) monitoring system 100 in accordancewith certain embodiments. Embodiments of the subject disclosure arefurther described primarily with respect to glucose monitoring devicesand systems, and methods of glucose detection, for convenience only andsuch description is in no way intended to limit the scope of thedisclosure. It is to be understood that the analyte monitoring systemmay be configured to monitor a variety of analytes at the same time orat different times.

Analytes that may be monitored include, but are not limited to, acetylcholine, amylase, bilirubin, cholesterol, chorionic gonadotropin,creatine kinase (e.g., CK-MB), creatine, creatinine, DNA, fructosamine,glucose, glutamine, growth hormones, hormones, ketone bodies, lactate,peroxide, prostate-specific antigen, prothrombin, RNA, thyroidstimulating hormone, and troponin. The concentration of drugs, such as,for example, antibiotics (e.g., gentamicin, vancomycin, and the like),digitoxin, digoxin, drugs of abuse, theophylline, and warfarin, may alsobe monitored. In those embodiments that monitor more than one analyte,the analytes may be monitored at the same or different times.

The analyte monitoring system 100 includes a sensor 101, a dataprocessing unit 102 connectable to the sensor 101, and a primaryreceiver unit 104 which is configured to communicate with the dataprocessing unit 102 via a communication link 103. In certainembodiments, the primary receiver unit 104 may be further configured totransmit data to a data processing terminal 105 to evaluate or otherwiseprocess or format data received by the primary receiver unit 104. Thedata processing terminal 105 may be configured to receive data directlyfrom the data processing unit 102 via a communication link which mayoptionally be configured for bi-directional communication. Further, thedata processing unit 102 may include a transmitter or a transceiver totransmit and/or receive data to and/or from the primary receiver unit104 and/or the data processing terminal 105 and/or optionally thesecondary receiver unit 106.

Also shown in FIG. 1 is an optional secondary receiver unit 106 which isoperatively coupled to the communication link and configured to receivedata transmitted from the data processing unit 102. The secondaryreceiver unit 106 may be configured to communicate with the primaryreceiver unit 104, as well as the data processing terminal 105. Thesecondary receiver unit 106 may be configured for bi-directionalwireless communication with each of the primary receiver unit 104 andthe data processing terminal 105. As discussed in further detail below,in certain embodiments the secondary receiver unit 106 may be ade-featured receiver as compared to the primary receiver, i.e., thesecondary receiver may include a limited or minimal number of functionsand features as compared with the primary receiver unit 104. As such,the secondary receiver unit 106 may include a smaller (in one or more,including all, dimensions), compact housing or embodied in a device suchas a wrist watch, arm band, etc., for example. Alternatively, thesecondary receiver unit 106 may be configured with the same orsubstantially similar functions and features as the primary receiverunit 104. The secondary receiver unit 106 may include a docking portionto be mated with a docking cradle unit for placement by, e.g., thebedside for night time monitoring, and/or a bi-directional communicationdevice. A docking cradle may recharge a powers supply.

Only one sensor 101, data processing unit or control unit 102 and dataprocessing terminal 105 are shown in the embodiment of the analytemonitoring system 100 illustrated in FIG. 1. However, it will beappreciated by one of ordinary skill in the art that the analytemonitoring system 100 may include more than one sensor 101 and/or morethan one data processing unit 102, and/or more than one data processingterminal 105. Multiple sensors may be positioned in a patient foranalyte monitoring at the same or different times. In certainembodiments, analyte information obtained by a first positioned sensormay be employed as a comparison to analyte information obtained by asecond sensor. This may be useful to confirm or validate analyteinformation obtained from one or both of the sensors. Such redundancymay be useful if analyte information is contemplated in criticaltherapy-related decisions. In certain embodiments, a first sensor may beused to calibrate a second sensor.

The analyte monitoring system 100 may be a continuous monitoring system,or semi-continuous, or a discrete monitoring system. In amulti-component environment, each component may be configured to beuniquely identified by one or more of the other components in the systemso that communication conflict may be readily resolved between thevarious components within the analyte monitoring system 100. Forexample, unique IDs, communication channels, and the like, may be used.

In certain embodiments, the sensor 101 is physically positioned in or onthe body of a user whose analyte level is being monitored. The sensor101 may be configured to at least periodically sample the analyte levelof the user and convert the sampled analyte level into a correspondingsignal for transmission by the data processing unit 102. The dataprocessing unit 102 is coupleable to the sensor 101 so that both devicesare positioned in or on the user's body, with at least a portion of theanalyte sensor 101 positioned transcutaneously. The data processing unitmay include a fixation element such as adhesive or the like to secure itto the user's body. A mount (not shown) attachable to the user andmateable with the unit 102 may be used. For example, a mount may includean adhesive surface. The data processing unit 102 performs dataprocessing functions, where such functions may include but are notlimited to, amplification, filtering and encoding of data signals, eachof which corresponds to a sampled analyte level of the user, fortransmission to the primary receiver unit 104 via the communication link103. In one embodiment, the sensor 101 or the data processing unit 102or a combined sensor/data processing unit may be wholly implantableunder the skin layer of the user.

In certain embodiments, the primary receiver unit 104 may include ananalog interface section including an RF receiver and an antenna that isconfigured to communicate with the data processing unit 102 via thecommunication link 103, and a data processing section for processing thereceived data from the data processing unit 102 such as data decoding,error detection and correction, data clock generation, data bitrecovery, etc., or any combination thereof.

In operation, the primary receiver unit 104 in certain embodiments isconfigured to synchronize with the data processing unit 102 to uniquelyidentify the data processing unit 102, based on, for example, anidentification information of the data processing unit 102, andthereafter, to periodically receive signals transmitted from the dataprocessing unit 102 associated with the monitored analyte levelsdetected by the sensor 101.

Referring again to FIG. 1, the data processing terminal 105 may includea personal computer, a portable computer such as a laptop or a handhelddevice (e.g., personal digital assistants (PDAs), telephone such as acellular phone (e.g., a multimedia and Internet-enabled mobile phonesuch as an iPhone or similar phone), mp3 player, pager, and the like),drug delivery device, each of which may be configured for datacommunication with the receiver via a wired or a wireless connection.Additionally, the data processing terminal 105 may further be connectedto a data network (not shown) for storing, retrieving, updating, and/oranalyzing data corresponding to the detected analyte level of the user.

The data processing terminal 105 may include an infusion device such asan insulin infusion pump or the like, which may be configured toadminister insulin to patients, and which may be configured tocommunicate with the primary receiver unit 104 for receiving, amongothers, the measured analyte level. Alternatively, the primary receiverunit 104 may be configured to integrate an infusion device therein sothat the primary receiver unit 104 is configured to administer insulin(or other appropriate drug) therapy to patients, for example, foradministering and modifying basal profiles, as well as for determiningappropriate boluses for administration based on, among others, thedetected analyte levels received from the data processing unit 102. Aninfusion device may be an external device or an internal device (whollyimplantable in a user).

In certain embodiments, the data processing terminal 105, which mayinclude an insulin pump, may be configured to receive the analytesignals from the data processing unit 102, and thus, incorporate thefunctions of the primary receiver unit 104 including data processing formanaging the patient's insulin therapy and analyte monitoring. Incertain embodiments, the communication link 103 as well as one or moreof the other communication interfaces shown in FIG. 1, may use one ormore of: an RF communication protocol, an infrared communicationprotocol, a Bluetooth enabled communication protocol, an 802.11xwireless communication protocol, or an equivalent wireless communicationprotocol which would allow secure, wireless communication of severalunits (for example, per HIPPA requirements), while avoiding potentialdata collision and interference.

FIG. 2 shows a block diagram of an embodiment of a data processing unitof the data monitoring and detection system shown in FIG. 1. User inputand/or interface components may be included or a data processing unitmay be free of user input and/or interface components. In certainembodiments, one or more application-specific integrated circuits (ASIC)may be used to implement one or more functions or routines associatedwith the operations of the data processing unit (and/or receiver unit)using for example one or more state machines and buffers. The processorshown in FIG. 2 may be equipped with sufficient memory to store the dataof interest (such as analyte data) for extended periods of time rangingfrom one to several samples to the number of samples obtained for anentire wear period of several days to weeks. In one aspect, the memorymay be included as part of the processor 204. In another embodiment, aseparate memory unit such as a memory chip, random access memory (RAM)or any other storage device for storing for subsequent retrieval data.For example, as shown, the data processing unit may include a storageunit 215 operative coupled to the processor 204, and configured to storethe analyte data received, for example, from the sensor 101 (FIG. 1). Inone aspect, the storage unit 215 may be configured to store a largevolume of data received over a predetermined time period from thesensor, and, the processor 204 may be configured to, for example,transmit the stored analyte sensor data in a batch mode, for example,after collecting and storing over a defined time period in a single ormultiple data transmission. In another aspect, the processor 204 may beconfigured such that the received analyte sensor data is e transmittedin real time, when received from the analyte sensor.

Also, the processor 204 may be configured to anticipate or wait for areceipt confirmation signal from the recipient of the data transmission(for example, the receiver unit 104 FIG. 1), where when the signalreceipt confirmation signal is not received, the processor 204 of thedata processing unit 102 may be configured to retrieve the storedanalyte sensor data and retransmit it to the receiver unit 104, forexample.

As can be seen in the embodiment of FIG. 2, the sensor unit 101 (FIG. 1)includes four contacts, three of which are electrodes—work electrode (W)210, reference electrode (R) 212, and counter electrode (C) 213, eachoperatively coupled to the analog interface 201 of the data processingunit 102. This embodiment also shows optional guard contact (G) 211.Fewer or greater electrodes may be employed. For example, the counterand reference electrode functions may be served by a singlecounter/reference electrode, there may be more than one workingelectrode and/or reference electrode and/or counter electrode, etc.

FIG. 3 is a block diagram of an embodiment of a receiver/monitor unitsuch as the primary receiver unit 104 of the data monitoring andmanagement system shown in FIG. 1. The primary receiver unit 104includes one or more of: a blood glucose test strip interface 301, an RFreceiver 302, an input 303, a temperature detection section 304, and aclock 305, each of which is operatively coupled to a processing andstorage section 307. The primary receiver unit 104 also includes a powersupply 306 operatively coupled to a power conversion and monitoringsection 308. Further, the power conversion and monitoring section 308 isalso coupled to the receiver processor 307. Moreover, also shown are areceiver serial communication section 309, and an output 310, eachoperatively coupled to the processing and storage unit 307. The receivermay include user input and/or interface components or may be free ofuser input and/or interface components.

In certain embodiments, the test strip interface 301 includes a glucoselevel testing portion to receive a blood (or other body fluid sample)glucose test or information related thereto. For example, the interfacemay include a test strip port to receive a glucose test strip. Thedevice may determine the glucose level of the test strip, and optionallydisplay (or otherwise notice) the glucose level on the output 310 of theprimary receiver unit 104. Any suitable test strip may be employed,e.g., test strips that only require a very small amount (e.g., onemicroliter or less, e.g., 0.5 microliter or less, e.g., 0.1 microliteror less), of applied sample to the strip in order to obtain accurateglucose information, e.g. FreeStyle® blood glucose test strips fromAbbott Diabetes Care Inc. Glucose information obtained by the in vitroglucose testing device may be used for a variety of purposes,computations, etc. For example, the information may be used to calibratesensor 101, confirm results of the sensor 101 to increase the confidencethereof (e.g., in instances in which information obtained by sensor 101is employed in therapy related decisions), etc.

In further embodiments, the data processing unit 102 and/or the primaryreceiver unit 104 and/or the secondary receiver unit 105, and/or thedata processing terminal/infusion section 105 may be configured toreceive the blood glucose value wirelessly over a communication linkfrom, for example, a blood glucose meter. In further embodiments, a usermanipulating or using the analyte monitoring system 100 (FIG. 1) maymanually input the blood glucose value using, for example, a userinterface (for example, a keyboard, keypad, voice commands, and thelike) incorporated in the one or more of the data processing unit 102,the primary receiver unit 104, secondary receiver unit 105, or the dataprocessing terminal/infusion section 105.

Additional detailed description of embodiments of test strips, bloodglucose (BG) meters and continuous monitoring systems and datamanagement systems that may be employed are provided in but not limitedto: U.S. Pat. No. 6,175,752; U.S. Pat. No. 6,560,471; U.S. Pat. No.5,262,035; U.S. Pat. No. 6,881,551; U.S. Pat. No. 6,121,009; U.S. Pat.No. 7,167,818; U.S. Pat. No. 6,270,455; U.S. Pat. No. 6,161,095; U.S.Pat. No. 5,918,603; U.S. Pat. No. 6,144,837; U.S. Pat. No. 5,601,435;U.S. Pat. No. 5,822,715; U.S. Pat. No. 5,899,855; U.S. Pat. No.6,071,391; U.S. Pat. No. 6,120,676; U.S. Pat. No. 6,143,164; U.S. Pat.No. 6,299,757; U.S. Pat. No. 6,338,790; U.S. Pat. No. 6,377,894; U.S.Pat. No. 6,600,997; U.S. Pat. No. 6,773,671; U.S. Pat. No. 6,514,460;U.S. Pat. No. 6,592,745; U.S. Pat. No. 5,628,890; U.S. Pat. No.5,820,551; U.S. Pat. No. 6,736,957; U.S. Pat. No. 4,545,382; U.S. Pat.No. 4,711,245; U.S. Pat. No. 5,509,410; U.S. Pat. No. 6,540,891; U.S.Pat. No. 6,730,200; U.S. Pat. No. 6,764,581; U.S. Pat. No. 6,299,757;U.S. Pat. No. 6,461,496; U.S. Pat. No. 6,503,381; U.S. Pat. No.6,591,125; U.S. Pat. No. 6,616,819; U.S. Pat. No. 6,618,934; U.S. Pat.No. 6,676,816; U.S. Pat. No. 6,749,740; U.S. Pat. No. 6,893,545; U.S.Pat. No. 6,942,518; U.S. Pat. No. 6,514,718; U.S. patent applicationSer. No. 10/745,878 filed Dec. 26, 2003 entitled “Continuous GlucoseMonitoring System and Methods of Use”, and elsewhere, the disclosures ofeach which are incorporated herein by reference for all purposes.

FIG. 4 schematically shows an embodiment of an analyte sensor inaccordance with the present disclosure. This sensor embodiment includeselectrodes 401, 402 and 403 on a base 404. Electrodes (and/or otherfeatures) may be applied or otherwise processed using any suitabletechnology, e.g., chemical vapor deposition (CVD), physical vapordeposition, sputtering, reactive sputtering, printing, coating, ablating(e.g., laser ablation), painting, dip coating, etching, and the like.Materials include but are not limited to aluminum, carbon (such asgraphite), cobalt, copper, gallium, gold, indium, iridium, iron, lead,magnesium, mercury (as an amalgam), nickel, niobium, osmium, palladium,platinum, rhenium, rhodium, selenium, silicon (e.g., dopedpolycrystalline silicon), silver, tantalum, tin, titanium, tungsten,uranium, vanadium, zinc, zirconium, mixtures thereof, and alloys,oxides, or metallic compounds of these elements.

The sensor may be wholly implantable in a user or may be configured sothat only a portion is positioned within (internal) a user and anotherportion outside (external) a user. For example, the sensor 400 mayinclude a portion positionable above a surface of the skin 410, and aportion positioned below the skin. In such embodiments, the externalportion may include contacts (connected to respective electrodes of thesecond portion by traces) to connect to another device also external tothe user such as a transmitter unit. While the embodiment of FIG. 4shows three electrodes side-by-side on the same surface of base 404,other configurations are contemplated, e.g., fewer or greaterelectrodes, some or all electrodes on different surfaces of the base orpresent on another base, some or all electrodes stacked together,electrodes of differing materials and dimensions, etc.

FIG. 5A shows a perspective view of an embodiment of an electrochemicalanalyte sensor 500 having a first portion (which in this embodiment maybe characterized as a major portion) positionable above a surface of theskin 510, and a second portion (which in this embodiment may becharacterized as a minor portion) that includes an insertion tip 530positionable below the skin, e.g., penetrating through the skin andinto, e.g., the subcutaneous space 520, in contact with the user'sbiofluid such as interstitial fluid. Contact portions of a workingelectrode 501, a reference electrode 502, and a counter electrode 503are positioned on the portion of the sensor 500 situated above the skinsurface 510. Working electrode 501, a reference electrode 502, and acounter electrode 503 are shown at the second section and particularlyat the insertion tip 530. Traces may be provided from the electrode atthe tip to the contact, as shown in FIG. 5A. It is to be understood thatgreater or fewer electrodes may be provided on a sensor. For example, asensor may include more than one working electrode and/or the counterand reference electrodes may be a single counter/reference electrode,etc.

FIG. 5B shows a cross sectional view of a portion of the sensor 500 ofFIG. 5A. The electrodes 510, 502 and 503, of the sensor 500 as well asthe substrate and the dielectric layers are provided in a layeredconfiguration or construction. For example, as shown in FIG. 5B, in oneaspect, the sensor 500 (such as the sensor unit 101 FIG. 1), includes asubstrate layer 504, and a first conducting layer 501 such as carbon,gold, etc., disposed on at least a portion of the substrate layer 504,and which may provide the working electrode. Also shown disposed on atleast a portion of the first conducting layer 501 is a sensing layer508.

A first insulation layer such as a first dielectric layer 505 isdisposed or layered on at least a portion of the first conducting layer501, and further, a second conducting layer 509 may be disposed orstacked on top of at least a portion of the first insulation layer (ordielectric layer) 505. As shown in FIG. 5B, the second conducting layer509 may provide the reference electrode 502, and in one aspect, mayinclude a layer of silver/silver chloride (Ag/AgCl), gold, etc.

A second insulation layer 506 such as a dielectric layer in oneembodiment may be disposed or layered on at least a portion of thesecond conducting layer 509. Further, a third conducting layer 503 mayprovide the counter electrode 503. It may be disposed on at least aportion of the second insulation layer 506. Finally, a third insulationlayer may be disposed or layered on at least a portion of the thirdconducting layer 503. In this manner, the sensor 500 may be layered suchthat at least a portion of each of the conducting layers is separated bya respective insulation layer (for example, a dielectric layer). Theembodiment of FIGS. 5A and 5B show the layers having different lengths.Some or all of the layers may have the same or different lengths and/orwidths.

In certain embodiments, some or all of the electrodes 501, 502, 503 maybe provided on the same side of the substrate 504 in the layeredconstruction as described above, or alternatively, may be provided in aco-planar manner such that two or more electrodes may be positioned onthe same plane (e.g., side-by side (e.g., parallel) or angled relativeto each other) on the substrate 504. For example, co-planar electrodesmay include a suitable spacing there between and/or include dielectricmaterial or insulation material disposed between the conductinglayers/electrodes. Furthermore, in certain embodiments one or more ofthe electrodes 501, 502, 503 may be disposed on opposing sides of thesubstrate 504. In such embodiments, contact pads may be one the same ordifferent sides of the substrate. For example, an electrode may be on afirst side and its respective contact may be on a second side, e.g., atrace connecting the electrode and the contact may traverse through thesubstrate.

As noted above, analyte sensors may include an analyte-responsive enzymeto provide a sensing component or sensing layer. Some analytes, such asoxygen, can be directly electrooxidized or electroreduced on a sensor,and more specifically at least on a working electrode of a sensor. Otheranalytes, such as glucose and lactate, require the presence of at leastone electron transfer agent and/or at least one catalyst to facilitatethe electrooxidation or electroreduction of the analyte. Catalysts mayalso be used for those analyte, such as oxygen, that can be directlyelectrooxidized or electroreduced on the working electrode. For theseanalytes, each working electrode includes a sensing layer (see forexample sensing layer 408 of FIG. 5B) proximate to or on a surface of aworking electrode. In many embodiments, a sensing layer is formed nearor on only a small portion of at least a working electrode.

The sensing layer includes one or more components designed to facilitatethe electrochemical oxidation or reduction of the analyte. The sensinglayer may include, for example, a catalyst to catalyze a reaction of theanalyte and produce a response at the working electrode, an electrontransfer agent to transfer electrons between the analyte and the workingelectrode (or other component), or both.

A variety of different sensing layer configurations may be used. Incertain embodiments, the sensing layer is deposited on the conductivematerial of a working electrode. The sensing layer may extend beyond theconductive material of the working electrode. In some cases, the sensinglayer may also extend over other electrodes, e.g., over the counterelectrode and/or reference electrode (or counter/reference is provided).

A sensing layer that is in direct contact with the working electrode maycontain an electron transfer agent to transfer electrons directly orindirectly between the analyte and the working electrode, and/or acatalyst to facilitate a reaction of the analyte. For example, aglucose, lactate, or oxygen electrode may be formed having a sensinglayer which contains a catalyst, such as glucose oxidase, lactateoxidase, or laccase, respectively, and an electron transfer agent thatfacilitates the electrooxidation of the glucose, lactate, or oxygen,respectively.

In other embodiments the sensing layer is not deposited directly on theworking electrode. Instead, the sensing layer 64 may be spaced apartfrom the working electrode, and separated from the working electrode,e.g., by a separation layer. A separation layer may include one or moremembranes or films or a physical distance. In addition to separating theworking electrode from the sensing layer the separation layer may alsoact as a mass transport limiting layer and/or an interferent eliminatinglayer and/or a biocompatible layer.

In certain embodiments which include more than one working electrode,one or more of the working electrodes may not have a correspondingsensing layer, or may have a sensing layer which does not contain one ormore components (e.g., an electron transfer agent and/or catalyst)needed to electrolyze the analyte. Thus, the signal at this workingelectrode may correspond to background signal which may be removed fromthe analyte signal obtained from one or more other working electrodesthat are associated with fully-functional sensing layers by, forexample, subtracting the signal.

In certain embodiments, the sensing layer includes one or more electrontransfer agents. Electron transfer agents that may be employed areelectroreducible and electrooxidizable ions or molecules having redoxpotentials that are a few hundred millivolts above or below the redoxpotential of the standard calomel electrode (SCE). The electron transferagent may be organic, organometallic, or inorganic. Examples of organicredox species are quinones and species that in their oxidized state havequinoid structures, such as Nile blue and indophenol. Examples oforganometallic redox species are metallocenes such as ferrocene.Examples of inorganic redox species are hexacyanoferrate (III),ruthenium hexamine etc.

In certain embodiments, electron transfer agents have structures orcharges which prevent or substantially reduce the diffusional loss ofthe electron transfer agent during the period of time that the sample isbeing analyzed. For example, electron transfer agents include but arenot limited to a redox species, e.g., bound to a polymer which can inturn be disposed on or near the working electrode. The bond between theredox species and the polymer may be covalent, coordinative, or ionic.Although any organic, organometallic or inorganic redox species may bebound to a polymer and used as an electron transfer agent, in certainembodiments the redox species is a transition metal compound or complex,e.g., osmium, ruthenium, iron, and cobalt compounds or complexes. Itwill be recognized that many redox species described for use with apolymeric component may also be used, without a polymeric component.

One type of polymeric electron transfer agent contains a redox speciescovalently bound in a polymeric composition. An example of this type ofmediator is poly(vinylferrocene). Another type of electron transferagent contains an ionically-bound redox species. This type of mediatormay include a charged polymer coupled to an oppositely charged redoxspecies. Examples of this type of mediator include a negatively chargedpolymer coupled to a positively charged redox species such as an osmiumor ruthenium polypyridyl cation. Another example of an ionically-boundmediator is a positively charged polymer such as quaternizedpoly(4-vinyl pyridine) or poly(1-vinyl imidazole) coupled to anegatively charged redox species such as ferricyanide or ferrocyanide.In other embodiments, electron transfer agents include a redox speciescoordinatively bound to a polymer. For example, the mediator may beformed by coordination of an osmium or cobalt 2,2′-bipyridyl complex topoly(1-vinyl imidazole) or poly(4-vinyl pyridine).

Suitable electron transfer agents are osmium transition metal complexeswith one or more ligands, each ligand having a nitrogen-containingheterocycle such as 2,2′-bipyridine, 1,10-phenanthroline, 1-methyl,2-pyridyl biimidazole, or derivatives thereof. The electron transferagents may also have one or more ligands covalently bound in a polymer,each ligand having at least one nitrogen-containing heterocycle, such aspyridine, imidazole, or derivatives thereof. One example of an electrontransfer agent includes (a) a polymer or copolymer having pyridine orimidazole functional groups and (b) osmium cations complexed with twoligands, each ligand containing 2,2′-bipyridine, 1,10-phenanthroline, orderivatives thereof, the two ligands not necessarily being the same.Some derivatives of 2,2′-bipyridine for complexation with the osmiumcation include but are not limited to 4,4′-dimethyl-2,2′-bipyridine andmono-, di-, and polyalkoxy-2,2′-bipyridines, such as4,4′-dimethoxy-2,2′-bipyridine. Derivatives of 1,10-phenanthroline forcomplexation with the osmium cation include but are not limited to4,7-dimethyl-1,10-phenanthroline and mono, di-, andpolyalkoxy-1,10-phenanthrolines, such as4,7-dimethoxy-1,10-phenanthroline. Polymers for complexation with theosmium cation include but are not limited to polymers and copolymers ofpoly(1-vinyl imidazole) (referred to as “PVI”) and poly(4-vinylpyridine) (referred to as “PVP”). Suitable copolymer substituents ofpoly(1-vinyl imidazole) include acrylonitrile, acrylamide, andsubstituted or quaternized N-vinyl imidazole, e.g., electron transferagents with osmium complexed to a polymer or copolymer of poly(1-vinylimidazole).

Embodiments may employ electron transfer agents having a redox potentialranging from about −200 mV to about +200 mV versus the standard calomelelectrode (SCE). The sensing layer may also include a catalyst which iscapable of catalyzing a reaction of the analyte. The catalyst may also,in some embodiments, act as an electron transfer agent. One example of asuitable catalyst is an enzyme which catalyzes a reaction of theanalyte. For example, a catalyst, such as a glucose oxidase, glucosedehydrogenase (e.g., pyrroloquinoline quinone (PQQ), dependent glucosedehydrogenase, flavine adenine dinucleotide (FAD) dependent glucosedehydrogenase, or nicotinamide adenine dinucleotide (NAD) dependentglucose dehydrogenase), may be used when the analyte of interest isglucose. A lactate oxidase or lactate dehydrogenase may be used when theanalyte of interest is lactate. Laccase may be used when the analyte ofinterest is oxygen or when oxygen is generated or consumed in responseto a reaction of the analyte.

The sensing layer may also include a catalyst which is capable ofcatalyzing a reaction of the analyte. The catalyst may also, in someembodiments, act as an electron transfer agent. One example of asuitable catalyst is an enzyme which catalyzes a reaction of theanalyte. For example, a catalyst, such as a glucose oxidase, glucosedehydrogenase (e.g., pyrroloquinoline quinone (PQQ), dependent glucosedehydrogenase or oligosaccharide dehydrogenase, flavine adeninedinucleotide (FAD) dependent glucose dehydrogenase, nicotinamide adeninedinucleotide (NAD) dependent glucose dehydrogenase), may be used whenthe analyte of interest is glucose. A lactate oxidase or lactatedehydrogenase may be used when the analyte of interest is lactate.Laccase may be used when the analyte of interest is oxygen or whenoxygen is generated or consumed in response to a reaction of theanalyte.

In certain embodiments, a catalyst may be attached to a polymer, crosslinking the catalyst with another electron transfer agent (which, asdescribed above, may be polymeric. A second catalyst may also be used incertain embodiments. This second catalyst may be used to catalyze areaction of a product compound resulting from the catalyzed reaction ofthe analyte. The second catalyst may operate with an electron transferagent to electrolyze the product compound to generate a signal at theworking electrode. Alternatively, a second catalyst may be provided inan interferent-eliminating layer to catalyze reactions that removeinterferents.

Certain embodiments include a Wired Enzyme™ sensing layer (AbbottDiabetes Care, Inc.) that works at a gentle oxidizing potential, e.g., apotential of about +40 mV. This sensing layer uses an osmium (Os)-basedmediator designed for low potential operation and is stably anchored ina polymeric layer. Accordingly, in certain embodiments the sensingelement is redox active component that includes (1) Osmium-basedmediator molecules attached by stable (bidente) ligands anchored to apolymeric backbone, and (2) glucose oxidase enzyme molecules. These twoconstituents are crosslinked together.

A mass transport limiting layer (not shown), e.g., an analyte fluxmodulating layer, may be included with the sensor to act as adiffusion-limiting barrier to reduce the rate of mass transport of theanalyte, for example, glucose or lactate, into the region around theworking electrodes. The mass transport limiting layers are useful inlimiting the flux of an analyte to a working electrode in anelectrochemical sensor so that the sensor is linearly responsive over alarge range of analyte concentrations and is easily calibrated. Masstransport limiting layers may include polymers and may be biocompatible.A mass transport limiting layer may provide many functions, e.g.,biocompatibility and/or interferent-eliminating, etc.

In certain embodiments, a mass transport limiting layer is a membranecomposed of crosslinked polymers containing heterocyclic nitrogengroups, such as polymers of polyvinylpyridine and polyvinylimidazole.Embodiments also include membranes that are made of a polyurethane, orpolyether urethane, or chemically related material, or membranes thatare made of silicone, and the like.

A membrane may be formed by crosslinking in situ a polymer, modifiedwith a zwitterionic moiety, a non-pyridine copolymer component, andoptionally another moiety that is either hydrophilic or hydrophobic,and/or has other desirable properties, in an alcohol-buffer solution.The modified polymer may be made from a precursor polymer containingheterocyclic nitrogen groups. For example, a precursor polymer may bepolyvinylpyridine or polyvinylimidazole. Optionally, hydrophilic orhydrophobic modifiers may be used to “fine-tune” the permeability of theresulting membrane to an analyte of interest. Optional hydrophilicmodifiers, such as poly(ethylene glycol), hydroxyl or polyhydroxylmodifiers, may be used to enhance the biocompatibility of the polymer orthe resulting membrane.

A membrane may be formed in situ by applying an alcohol-buffer solutionof a crosslinker and a modified polymer over an enzyme-containingsensing layer and allowing the solution to cure for about one to twodays or other appropriate time period. The crosslinker-polymer solutionmay be applied to the sensing layer by placing a droplet or droplets ofthe solution on the sensor, by dipping the sensor into the solution, orthe like. Generally, the thickness of the membrane is controlled by theconcentration of the solution, by the number of droplets of the solutionapplied, by the number of times the sensor is dipped in the solution, orby any combination of these factors. A membrane applied in this mannermay have any combination of the following functions: (1) mass transportlimitation, i.e. reduction of the flux of analyte that can reach thesensing layer, (2) biocompatibility enhancement, or (3) interferentreduction.

The description herein is directed primarily to electrochemical sensorsfor convenience only and is in no way intended to limit the scope of thedisclosure. Other sensors and sensor systems are contemplated. Suchinclude, but are not limited to, optical sensors, colorimetric sensors,potentiometric sensors, coulometric sensors and sensors that detecthydrogen peroxide to infer glucose levels, for example. For example, ahydrogen peroxide-detecting sensor may be constructed in which a sensinglayer includes enzyme such as glucose oxides, glucose dehydrogensae, orthe like, and is positioned proximate to the working electrode. Thesending layer may be covered by a membrane that is selectively permeableto glucose. Once the glucose passes through the membrane, it is oxidizedby the enzyme and reduced glucose oxidase can then be oxidized byreacting with molecular oxygen to produce hydrogen peroxide.

Certain embodiments include a hydrogen peroxide-detecting sensorconstructed from a sensing layer prepared by crosslinking two componentstogether, for example: (1) a redox compound such as a redox polymercontaining pendent Os polypyridyl complexes with oxidation potentials ofabout +200 mV vs. SCE, and (2) periodate oxidized horseradish peroxidase(HRP). Such a sensor functions in a reductive mode; the workingelectrode is controlled at a potential negative to that of the Oscomplex, resulting in mediated reduction of hydrogen peroxide throughthe HRP catalyst.

In another example, a potentiometric sensor can be constructed asfollows. A glucose-sensing layer is constructed by crosslinking together(1) a redox polymer containing pendent Os polypyridyl complexes withoxidation potentials from about −200 mV to +200 mV vs. SCE, and (2)glucose oxidase. This sensor can then be used in a potentiometric mode,by exposing the sensor to a glucose containing solution, underconditions of zero current flow, and allowing the ratio ofreduced/oxidized Os to reach an equilibrium value. The reduced/oxidizedOs ratio varies in a reproducible way with the glucose concentration,and will cause the electrode's potential to vary in a similar way.

A sensor may also include an active agent such as an anticlotting and/orantiglycolytic agent(s) disposed on at least a portion a sensor that ispositioned in a user. An anticlotting agent may reduce or eliminate theclotting of blood or other body fluid around the sensor, particularlyafter insertion of the sensor. Examples of useful anticlotting agentsinclude heparin and tissue plasminogen activator (TPA), as well as otherknown anticlotting agents. Embodiments may include an antiglycolyticagent or precursor thereof. Examples of antiglycolytic agents areglyceraldehyde, fluoride ion, and mannose.

Sensors may be configured to require no system calibration or no usercalibration. For example, a sensor may be factory calibrated and neednot require further calibrating. In certain embodiments, calibration maybe required, but may be done without user intervention, i.e., may beautomatic. In those embodiments in which calibration by the user isrequired, the calibration may be according to a predetermined scheduleor may be dynamic, i.e., the time for which may be determined by thesystem on a real-time basis according to various factors, such as butnot limited to glucose concentration and/or temperature and/or rate ofchange of glucose, etc.

Calibration may be accomplished using an in vitro test strip (or otherreference), e.g., a small sample test strip such as a test strip thatrequires less than about 1 microliter of sample (for example FreeStyle®blood glucose monitoring test strips from Abbott Diabetes Care). Forexample, test strips that require less than about 1 nanoliter of samplemay be used. In certain embodiments, a sensor may be calibrated usingonly one sample of body fluid per calibration event. For example, a userneed only lance a body part one time to obtain sample for a calibrationevent (e.g., for a test strip), or may lance more than one time within ashort period of time if an insufficient volume of sample is firstlyobtained. Embodiments include obtaining and using multiple samples ofbody fluid for a given calibration event, where glucose values of eachsample are substantially similar. Data obtained from a given calibrationevent may be used independently to calibrate or combined with dataobtained from previous calibration events, e.g., averaged includingweighted averaged, etc., to calibrate. In certain embodiments, a systemneed only be calibrated once by a user, where recalibration of thesystem is not required.

Analyte systems may include an optional alarm system that, e.g., basedon information from a processor, warns the patient of a potentiallydetrimental condition of the analyte. For example, if glucose is theanalyte, an alarm system may warn a user of conditions such ashypoglycemia and/or hyperglycemia and/or impending hypoglycemia, and/orimpending hyperglycemia. An alarm system may be triggered when analytelevels approach, reach or exceed a threshold value. An alarm system mayalso, or alternatively, be activated when the rate of change, oracceleration of the rate of change, in analyte level increase ordecrease approaches, reaches or exceeds a threshold rate oracceleration. A system may also include system alarms that notify a userof system information such as battery condition, calibration, sensordislodgment, sensor malfunction, etc. Alarms may be, for example,auditory and/or visual. Other sensory-stimulating alarm systems may beused including alarm systems which heat, cool, vibrate, or produce amild electrical shock when activated.

The subject disclosure also includes sensors used in sensor-based drugdelivery systems. The system may provide a drug to counteract the highor low level of the analyte in response to the signals from one or moresensors. Alternatively, the system may monitor the drug concentration toensure that the drug remains within a desired therapeutic range. Thedrug delivery system may include one or more (e.g., two or more)sensors, a processing unit such as a transmitter, a receiver/displayunit, and a drug administration system. In some cases, some or allcomponents may be integrated in a single unit. A sensor-based drugdelivery system may use data from the one or more sensors to providenecessary input for a control algorithm/mechanism to adjust theadministration of drugs, e.g., automatically or semi-automatically. Asan example, a glucose sensor may be used to control and adjust theadministration of insulin from an external or implanted insulin pump.

As discussed above, embodiments of the present disclosure relate tomethods and devices for detecting at least one analyte such as glucosein body fluid. Embodiments relate to the continuous and/or automatic invivo monitoring of the level of one or more analytes using a continuousanalyte monitoring system that includes an analyte sensor at least aportion of which is to be positioned beneath a skin surface of a userfor a period of time and/or the discrete monitoring of one or moreanalytes using an in vitro blood glucose (“BG”) meter in conjunctionwith an analyte test strip. Embodiments include combined or combinabledevices, systems and methods and/or transferring data between an in vivocontinuous system and a BG meter system, and include integrated systems.

Embodiments include “Data Logger” systems which include a continuousglucose monitoring system (at least an analyte sensor and control unit(e.g., an on body unit)). The continuous glucose monitoring (“CG”)system may have limited real-time connectivity with a BG meter. Forexample, real time connectivity may be limited to communicatingcalibration data (e.g., a BG value) to the CG system or it may have theability to receive data from the CG system on demand (as compared to aCG system continuously broadcasting such data). In one embodiment, thedata processing unit (102) may be an on-body unit that is configured tooperate in several transmission modes. In a first mode, analyte relateddata may be transmitted when a new data value (e.g., sensor data) isavailable (for example, when received from the analyte sensor). Thismode of operation may result in “lost data” because the data processingunit 102 does not get confirmation that the data was successfullyreceived by the receiver unit 104, and in some embodiments, this datamay not be resent.

In a second transmission mode, data may be transmitted when the new datais available and the data processing unit 102 may receive anacknowledgement that such data has been successfully received, or if thetransmission was unsuccessful the data would be stored (“buffered”) foranother attempt. This mode reduces the likelihood of “lost data”. In athird mode (“data logging mode”), the data processing unit 102 may beconfigured to retain or store all data (i.e.; not attempt to transmit itwhen it becomes available) until the receiver unit (104) requests thedata, or based upon a scheduled data transmission.

CG data obtained by the CG Data Logger may be processed by the DataLogger system or by the BG meter and/or by a data management system(“DMS”) which may includes a computer such as a PC and an optionalserver. For example, the CoPilot™ data management system from AbbottDiabetes Care, Inc., or the like, may be employed. In certainembodiments neither the CG system nor the BG meter are capable of (orhave such capability, but the capability is selectively turned off)supporting continuous real time CG data communication, therebysubstantially reducing power requirements. Such embodiments are CG DataLoggers in which CG data resides (i.e., is logged) in a CG control unit(e.g., on-body unit) until it is retrieved by a BG meter. In otherwords, a CG Data Logger buffers the CG data and stores it in memoryuntil the CG data is downloaded or transferred to the BG meter, e.g., auser initiates data transfer or transfer may occur at set times. The CGcomponent logs continuous glucose data, but only gives up this data tothe on-request to a BG meter. Retrieval may be by any suitablemethodology, including but not limited to wireless communicationprotocols such as for example RF, optical means (such as an IR link),Bluetooth, or a direct connection (such as a USB, or the like), etc. Agiven BG meter and CG data Logger may be synchronized, e.g., by one ormore unique identifiers, thereby ensuring preventing inadvertent dataexchange between devices.

FIG. 6 shows an exemplary embodiment of a system that includes a CG DataLogger and an enhanced BG meter. As shown, the enhanced BG meter maycommunicate with the CG Data Logger by a wired connection and/or by IRor RF. Referring to the Figure, in one aspect, the CG data logger may beconfigured to collect and store monitored analyte data over apredetermined time period (for example, from a transcutaneous,subcutaneous or implanted analyte sensor), and transmit the collectedand stored analyte data to the BG meter either continuously in realtime, or periodically (for example, when the CG data logger is in signalcommunication with the BG meter (either cabled or wireless), or in asingle data transfer mode, for example, at the end of the predeterminedtime period.

“Modular” embodiments are also provided. Modular systems may be used inconjunction with the Data Logger system in certain embodiments. Forexample, a separable CG data transfer module may be configured forwireless communication with the CG data logger and further configured toremovably mate with a BG meter to transfer CG information to the BGmeter (see for example FIG. 7). Modular embodiments include all thenecessary hardware (and software) to support either (or both) continuous(real time) or “batched” (data logged) CG data collection in a snap-onor otherwise mateable module that provides CG data to a BG meter. Alarmfunctionality may be included in the BG meter, as well as features tosupport CG data processing and communication to a user, e.g., hardwareand software to process CG data and/or calibrate CG data, enhanced userinterface to communicate CG information to a user (in addition to BGinformation), e.g., may include CG calibration information, CG trendinformation, rate of change indicators to indicate the rate of change ofglucose, and the like.

Modules may be re-usable by a plurality of users. User privacy featuresmay be included, e.g., a module may not permanently store patient data(user data may be automatically deleted or expunged after a certain timeperiod), data may be encrypted, password protected, or otherwiseprovided with one or more security features that will limit access toonly the intended users. In one aspect, the CG data logger may beconfigured to collect and store the monitored analyte data received froman analyte sensor, and upon establishing data communication with the BGmeter via the data transfer module, communicate the received analytedata in one or more batch transfer, or continuously in real time as theanalyte sensor data is received from the sensor.

FIG. 7 shows an exemplary embodiment of a modular system that includes aCG control unit/transmitter, a mateable module and an enhanced BG meter.In this embodiment, the CG data logger/transmitter is showncommunicating with the module via RF where the module is mateablycoupled to the BG meter. However, other suitable data communicationapproaches may be used including IR, Bluetooth, Zigbee communication,and the like.

FIG. 8 shows an integrated or continuous system that includes anenhanced BG meter and a CG data logger/transmitter, where the CG datalogger is capable of transferring CG data to the enhanced BG meterdirectly and in real time, in this embodiment shown via a wirelessprotocol. For example, as shown, the enhanced BG meter may include an RFcommunication module or chipset that allows for wireless communicationwith the CG data logger. Accordingly, as the continuous analyte sensordata is received by the CG data logger, the data is substantiallycontemporaneously transferred or communicated in real time to theenhanced BG meter over the RF communication link.

FIG. 9 shows an exemplary embodiment of a system which includes a BGmeter and a docking unit, herein shown configured as a belt holster. TheBG meter couples to the holster via contacts of the holster, whichcorrespond to contacts of the BG meter. The BG meter displaysinformation to the user when electronically coupled to the holster,i.e., when docked or when in wireless signal communication with the beltholster (for example, when removed from the holster). The holster mayinclude some or all functionality of a primary receiver unit asdescribed below for CG monitoring. For example, the holster may containsome or all of a FreeStyle Navigator® system, e.g., the receiverfunctionality as described above. In one aspect, the belt holster mayintegrate the CG data logger such that the collected and stored analytedata may be transferred to the BG meter when docked in the holster (orwhen wirelessly synchronized with the belt holster).

The CG system may be calibrated using the BG meter, e.g., when the BGmeter is docked. Such as system may be useful in a variety of instances,e.g., for gestational diabetes, assessing/diagnosing diabetes, and thelike.

In certain embodiments, the CG system (whether it be modular or includesa data logger) may be configured with reduced set of functionalities.For example, it may not include alarms (audible and/or vibratory and/orvisual) and/or glucose rate of change indicators and/or a visual or userinterface display such as a dot matrix display and/or additionalprocessing power and/or miniaturized, or it may not include a test stripport. For example, FIG. 10 illustrates features which may be included inan exemplary full-featured CG system, and exemplary integrated real timesystem and an exemplary Data Logger system.

In certain embodiments, synchronization between a BG and CG systems isprovided to calibrate the CG sensor using a BG strip measurement as areference data point.

In certain applications, the enhanced BG meters may be used by those whorequire more intensive (i.e., continuous) glucose monitoring, bytemporarily or periodically allowing a user's BG meter to capture CGdata without the user having to obtain another meter. Likewise, theadded value to a health care provider (“HCP”) is gained by patientsperiodically obtaining more detailed blood glucose information (e.g.,prior to regular check up), thus allowing the HCP to make more informedand suited therapy adjustments for the patient.

Various embodiments have extensive applicability. For example,indwelling or external sensors other than CG sensors may be included.Data from indwelling or external sensors other than a CG sensor may becaptured by the systems described herein (such as temperature data,ketone data, and the like). Furthermore, functions such as weighmanagement, enhanced data management or insulin pump control may also beadded to a BG meter via the modular approach to further enhance themeter. In certain embodiments, a Data Logger includes providing moldedelectrical contacts that allow for electrical connections thru theon-body case without compromising the watertight seal of the case.

Embodiments herein may provide increased value of a BG meter to thepatient by adding CG functionality to a base BG meter, a low learningcurve such that the user does not need to become familiar with twodifferent user interfaces (one for the BG unit and another for the CGsystem), reduction in cost of the overall system, and substantialimmunity to environments where continuous wireless communication may beprohibited such as during flight on an airplane, within hospital orother settings that have sensitive instrumentation that may interferewith RF or other wireless signals.

Accordingly, an analyte monitoring system in one embodiment includes ananalyte sensor for transcutaneous positioning under a skin layer of asubject, a data processing device operatively coupled to the analytesensor, the device comprising: a control unit, a memory operativelycoupled to the control unit and configured to store a plurality of dataassociated with the monitored analyte level received from the sensor,and a communication unit operatively coupled to the control unit; and ablood glucose meter configured for signal communication with the dataprocessing device, where when the control unit of the data processingdevice detects a communication link with the blood glucose meter, thecontrol unit is further configured to retrieve the stored plurality ofdata from the memory and to transmit the retrieved data to the bloodglucose meter.

The blood glucose meter includes a strip port for receiving a bloodglucose test strip.

The communication unit may be configured to communicate with the bloodglucose meter using one or more of a wired connection, a USB cableconnection, a serial cable connection, an RF communication protocol, aninfrared communication protocol, a Bluetooth communication protocol, oran 802.11x communication protocol.

In one embodiment, data processing device does not include a user outputcomponent, where the user output component includes a display.

The control unit may detect the communication link with the bloodglucose meter based on detection of a wired connection to the meter.

The retrieved stored plurality of data may correspond to glucose data ofthe subject collected over a predetermined time period.

The glucose data may be uncalibrated or calibrated.

The analyte sensor may be a glucose sensor.

In one aspect, the blood glucose meter may include an output unitconfigured to output one or more of the received retrieved data.

The output unit may include a display unit operatively coupled to ahousing of the blood glucose meter.

The output of one or more received data may include a graphical output,a numerical output, or a text output.

The blood glucose meter may be configured to calibrate the receiveddata.

The blood glucose meter may include a storage unit configured to storethe calibrated data.

The blood glucose meter may include a storage unit configured to storethe received data.

In another aspect, the system may include a holster device for receivingthe blood glucose meter, and the data processing unit may be integratedin the holster device.

The control unit may be configured to detect the communication link withthe blood glucose meter when the meter is coupled to the holster.

The holster device may include a belt clip.

A method in another embodiment may include transcutaneously positioningan analyte sensor under a skin layer of a subject, coupling a dataprocessing device to the analyte sensor, storing in a memory of the dataprocessing device a plurality of data associated with the monitoredanalyte level received from the sensor, operatively coupling acommunication unit to the control unit, detecting a communication linkwith the blood glucose meter, retrieving the stored plurality of datafrom the memory, and commanding the communication unit to transmit theretrieved data to the blood glucose meter.

The communication link may be established based on one or more of awired connection, a USB cable connection, a serial cable connection, anRF communication protocol, an infrared communication protocol, aBluetooth communication protocol, or an 802.11x communication protocol.

The method may include displaying on the blood glucose meter thereceived analyte data.

The retrieved data may correspond to glucose data of the subjectcollected over a predetermined time period.

The method may include calibrating the received data.

In another aspect, the method may include storing the received data in amemory of the blood glucose meter.

In still a further aspect, the method may include encrypting theretrieved data prior to transmitting to the blood glucose meter.

Various other modifications and alterations in the structure and methodof operation of the present disclosure will be apparent to those skilledin the art without departing from the scope and spirit of the presentdisclosure. Although the present disclosure has been described inconnection with specific embodiments, it should be understood that thepresent disclosure as claimed should not be unduly limited to suchspecific embodiments. It is intended that the following claims definethe scope of the present disclosure and that structures and methodswithin the scope of these claims and their equivalents be coveredthereby.

1. An analyte monitoring device, comprising: a housing; a communicationunit coupled to the housing; a data processing unit coupled to thehousing, the data processing unit generating a request for data relatedto a monitored analyte level, the request transmitted by thecommunication unit, the data processing unit processing the data relatedto the monitored analyte level received in response to the generatedrequest; and a memory operatively coupled to the data processing unitand configured to store the received data associated with the monitoredanalyte level or the processed data related to the monitored analytelevel or both.
 2. The device of claim 1 wherein the communication unittransmits the request or receives the data related to the monitoredanalyte level based on radio frequency (RF) communication.
 3. The deviceof claim 1 wherein the data processing unit generates an acknowledgementin response to the received data related to the monitored analyte level.4. The device of claim 1 further including a strip port operativelycoupled to the housing to receive an in vitro test strip.
 5. The deviceof claim 4 wherein the data processing unit determines a blood glucosemeasurement based on a sample received from the in vitro test strip. 6.The device of claim 1 wherein the communication unit communicates usingone or more of a wired connection, a universal serial bus (USB) cableconnection, a serial cable connection, an RF communication protocol, aninfrared (IR) communication protocol, a Bluetooth communicationprotocol, or an 802.11x communication protocol.
 7. The device of claim 1wherein the memory stores a blood glucose measurement based on a samplereceived from an in vitro test strip.
 8. The device of claim 1 furtherincluding an output component operatively coupled to the data processingunit to output one or more information related to the monitored analytelevel or a blood glucose measurement.
 9. The device of claim 8 whereinthe output component includes a display.
 10. The device of claim 9wherein the display includes one or more of a graphical output, anumerical output, or a text output.
 11. The device of claim 8 whereinthe output component includes an audible output.
 12. The device of claim11 wherein the data processing unit generates the audible output whenthe data related to the monitored analyte level is received.
 13. Thedevice of claim 1 wherein the data processing unit is configured toperform one or more of a retrospective analysis or a prospectiveanalysis of the received data related to the monitored analyte level.14. The device of claim 13 wherein the data processing unit performs theretrospective analysis of the received data related to the monitoredanalyte level based on a blood glucose measurement.
 15. The device ofclaim 13 wherein the data processing unit performs the prospectiveanalysis of the received data related to the monitored analyte level inreal time.
 16. A method, comprising: generating a request for datarelated to a monitored analyte level from an analyte sensor;transmitting the generated request based on radio frequency (RF)communication protocol; receiving the data related to the monitoredanalyte level in response to the transmitted request based on the RFcommunication protocol; and storing in a memory the received dataassociated with the monitored analyte level.
 17. The method of claim 16further including generating an acknowledgement in response to thereceived data related to the monitored analyte level.
 18. The method ofclaim 16 further including determining a blood glucose level based on ablood sample from an in vitro test strip.
 19. The method of claim 16further including outputting the received data related to the monitoredanalyte level.
 20. The method of claim 16 wherein the received datarelated to the monitored analyte level is associated with one or more ofa current monitored analyte level or a previous monitored analyte level.